Chris Hemsworth introduces young Optimus Prime in 'Transformers One' at Comic-Con

"How do two best friends become mortal enemies?" Hemsworth teases the origin story of Optimus Prime and Megatron.

At Comic-Con in San Diego, Chris Hemsworth, Keegan-Michael Key, and Brian Tyree Henry introduced the highly anticipated animated film "Transformers One," set to hit theaters on September 20. 

The movie delves into the origins of iconic "Transformers" rivals Optimus Prime and Megatron, exploring their friendship as Orion Pax (Hemsworth) and D-16 (Henry) on Cybertron 3 billion years ago. 

"How do two best friends become mortal enemies?" Hemsworth pondered during the presentation. 

The movie, directed by Josh Cooley, captures the nostalgia and joy of playing with "Transformers" toys, featuring rich lore and a plot that would have cost $500 million to produce in live action, according to producer Lorenzo di Bonaventura.

Before becoming the legendary Optimus and Megatron, Orion Pax and D-16 were miners caught in an adventure with B-127 (Key) and Elita-1 (Scarlett Johansson). 

Hemsworth honored Peter Cullen, the original voice of Optimus Prime, while highlighting his approach to portraying a younger, cockier version of the character. 

Henry shared his take on Megatron, emphasizing the character's sense of precociousness before his transformation into a villain.

Cooley assured fans that "Transformers One" would include Easter eggs and familiar characters from the franchise's 40-year history, with a supporting cast featuring Jon Hamm as Sentinel Prime, Laurence Fishburne as Alpha Trion, and Steve Buscemi as Starscream. 

The actors also reminisced about their childhood memories with "Transformers" toys, with Henry recalling his collection of villain toys and Key leading the crowd in singing the '80s cartoon theme song.